unclear refractometer reading

[piteko]

Hello everybody,
I recently broke the densimeter cylinder. Trying to replace it, I broke the densimeter too. I saw it as my karma telling me to buy a refractometer, as I was looking forward to do that since a long time.

When I used it for the first time during the mash and the boil, I had no problems. When it came to check the fermentation, I had a very unclear reading, as you can see in the picture attached. I don't know if it can help understand why, but I used a lot of flacked barley, had a huge filtering problem and had a massive load of powder in the fermentor (but during the boil the reading was clear...).

Sample was taken from the top of the fermenter, opening the krausen, to avoid all the powder that was sitting on the fermenter bottom. Fermentor was Danstar Belle Saison.

I made 3 readings in 3 different days, same unclear result. Googled it online and checked the plastic cover to be completely flat on the glass, nothing changed. Tried with water, had a clear reading. The reading became clearer after I cold crashed the beer.

The real problem was that I crashed the densimeter, so I had no way to cross check the readings. I don't have temperature problems and I know the yeast, so beer came out good anyway.

What am I doing wrong?
Cheers from Italy!
Piteko

 

[HopHeavy]

Hi Piteko! Sorry to hear about your densimeter (hydrometer?) Unfortunately, I can't help explain the blurry refractometer reading. I just wanted to be sure you were aware that refractometer readings after pitching require adjustment, apparently because alcohol bends light differently than dissolved sugars. Take a look at one of the online calculators here. I have abandoned using the refractometer post fermentation for this reason.

 

[dshepard]

I have used a refractometer for years now and haven't seen anything like that. Maybe a defective refractometer? One thing I have noticed is that sunlight works much better than indoor lighting. You don't have to have the sun directly on it, just walking outdoors makes the delineation more pronounced. HopHeavy's comment is correct, but as mentioned the calculators are pretty darn close. I don't enter into competitions so I don't really care what the final reading is. The refractometer is nice in that it only takes a drop to check FG. I am really are only concerned with noticing when fermentation stops.

 

[millstone]

Mine has a focusing adjustment near the eye piece, could it be something that simple?

Tom

 

[hagar]

I'm fairly new to the refractometer; and in my novice-ness (if that ain't a word it is now) I've twisted the eyepiece all the way both ways. I've never seen it do that to the actual reading line.

I did a test just now with the flap completely up, I have a reasonably solid reading line anywhere a drop of liquid touches the glass. It looks like yours does where there is no liquid.

Tried to get a pic to show you what I mean, but I'm not co-ordinated enough, it seems.

 

[LKABrewer]

Make sure you only have one light source. Multiple light sources will blur the readings.

 

[piteko]

Sorry to hear about your densimeter (hydrometer?)

Yep, hydrometer (just invented that term as an english version of the italian term, sob, but today I saw that it's also called densitometer, so I got pretty close )

I just wanted to be sure you were aware that refractometer readings after pitching require adjustment, apparently because alcohol bends light differently than dissolved sugars.

Thanks for the suggestion, I was aware. Blurred readings and formulas aren't the easiest way to take a gravity reading, lol!!

Just to complicate the thing, when I cold crashed, I remembered I have a precision hydrometer (it's taller and has a thermometer inside), so I took a reading with that directly in the fermenter (I had it as a backup and never used it, so I hadn't a nice cylinder for it). The reading was a strange 1010, since Danstar Belle saison is extremely aggressive and I expected something like 1002-1004. The refractometer was telling 1003 and the taste was in line.
I later discovered that the precision hydrometer was so tall that it was pushing over the yeast cake, that's why it was so high!!

Cheers from Italy!
Piteko

 

[piteko]

Maybe a defective refractometer?

I don't know, during the boil the line was very clear. Today I tried a reading on another fermenting batch (the above was a wit fermented 3 weeks ago with danstar belle saison, this one is an american IPA fermented with US-05). The reading was clear enough to make a good reading but it's not clear as the one I get from water or worth and I took it from the faucet.

One thing I have noticed is that sunlight works much better than indoor lighting.

Thanks for the suggestion, I'll keep that in mind.
Cheers from Italy!
Piteko

 

[piteko]

Mine has a focusing adjustment near the eye piece, could it be something that simple?

I tried that. As you can see, the numbers are very readable. If I change the focusing adjustment, the numbers blur too. So I think that's the best reading I can get. Fortunally I made a shot with the smartphone, otherwise I bet nobody could believe me

Thanks for the response!
Cheers from Italy!
Piteko

 

[piteko]

I did a test just now with the flap completely up, I have a reasonably solid reading line anywhere a drop of liquid touches the glass. It looks like yours does where there is no liquid.

I'm completely sure the liquid was all over the glass. I had the problem for 3 readings in different days so I was very careful.
Unfortunally, when I had the problem I had too much to do to post it here, so I can't test it now (the beer has already been bottled). Anyway, I'll test the reading with the flap up, I'm curious

Thanks for the response!
Cheers from Italy!
Piteko

 

[stpug]

I would adjust the angle of the light to the crystal face to increase the contrast, AND I would filter the sample through a paper towel to reduce the particulate/yeast matter.

It looks like you're aiming the light at the crystal very perpendicularly, like this: --> |
You should decrease the angle the light hits the crystal to increase constrast, like this: --> ̷

As for filtering, you can use a 2x2 cm patch of paper towel, and make it into a little cone shape. Pour several drop into the cone, and squeeze them out the other side of the cone onto the lens.

 

[piteko]

Make sure you only have one light source. Multiple light sources will blur the readings.

I had the same feeling. Tried it with the light of my garage (where I brew) which is a energy saving bulb and outside. Same blurried reading. I thougth "maybe it's the yeast suspended or the debris from the brew". At the third day, I even thougth "maybe these are some little CO2 bubbles coming from the fermentation". I really had no clue and I was totally brainstorming.

I really regret not making a reading from the bottom of the fermenter, taking some beer from the faucet.

Thanks for the suggestion!
Cheers from Italy!
Piteko

 

[phug]

It must be suspended particulate in the beer

 

[Firewalker11]

I can never see the refractometer line clearly so I grabbed my LED flashlight and sighted it right in line with the length of the refractometer and it gives me a very clear line, even if there's debris in the wort.

 

[piteko]

I would filter the sample through a paper towel to reduce the particulate/yeast matter.

Now I'm really starting to regret not posting this while I had the problem! Thanks for the suggestion, I hope I'll never have this problem again, but if that will be the case, I'll be prepared!!

Cheers from Italy!
Piteko

 

[FlyDoctor]

I have had this problem, and it went away with a good strong light source as was mentioned. I was about to throw mine away it was such a pain. Now, happiness...works great - just make sure you have a good light and you are pointing it towards the light source.

 

[kh54s10]

The other option is to use the refractometer before fermentation and a hydrometer after fermentation. That way you get a true reading with the presence of alcohol and no calculations.

 

[FlyDoctor]

That's what I do, hydrometer post ferment. I got one of those bottling hydrometers - with a smaller range (? Max 1.030) to make it easier to read. From Williams brewing.

 

[IslandLizard]

Once you got this worked out, good suggestions above, don't forget to use one of the online calculators to convert your reading into the correct SG. Once alcohol is present in your sample (during or after fermentation) the refractometer will give you a much higher SG reading than it really is. Hence the correction calculator. You will need to know the OG to use it.

 

[Firewalker11]

Once you got this worked out, good suggestions above, don't forget to use one of the online calculators to convert your reading into the correct SG. Once alcohol is present in your sample (during or after fermentation) the refractometer will give you a much higher SG reading than it really is. Hence the correction calculator. You will need to know the OG to use it.

It's built into BeerSmith under 'tools' as well.

 

[piteko]

Once you got this worked out, good suggestions above, don't forget to use one of the online calculators to convert your reading into the correct SG.

Thanks, I looked online for the formula and made a simple OpenOffice calculator for the convertion.

Cheers from Italy!
Piteko